Andreas Shimokawa 7ffcc44378 Pebble: fix nasty crash when appmessage id is > 127
This is a regression since Gadgetbridge 0.22.0

Potentially fixes the following:

- #868
- #876
- #884

NOTE:

Java has no unisgned, java has no unsigned, java has no unsigned.
Java has no unisgned, java has no unsigned, java has no unsigned.
Java has no unisgned, java has no unsigned, java has no unsigned.
2017-11-14 22:28:54 +01:00
..
2017-11-14 12:55:02 +01:00